In life, we experience big and small milestones, both which should be celebrated. Some of the major ones that we look forward to are getting married, new career moves, having a baby and moving to a new house.
When someone moves to a new home, a housewarming party often follows. This is where you gather your loved ones to celebrate this new change in your life and a way of settling into your new space, which is basically "warming" a house.